One Minute Mentor: Plasma Nitriding Equipment

Cold-walled (double-walled water-cooled) systems were the first generation of plasma nitriding furnaces. This technology is also a vacuum-based process but employs the principle of glow discharge to provide energy for heating and nitriding at one time. Therefore, the independent control of the temperature stability and the nitriding intensity is not possible because both processes are using the same energy source—the plasma.

The hot-wall plasma nitriding furnaces, the next generation of cold-wall ion nitriding systems, are mainly used and built now. This system ensures optimal nitriding quality by fulfilling the highest demands on temperature and nitriding process control. The big advantage of this technology is the separation of the control of the heating and the plasma nitriding parameters. The heating and temperature control of hot-wall plasma nitriding furnaces is realized by several independent heating/cooling zones, which guarantees optimal temperature homogeneity

For more information, click on the link below (subscription required). Then scroll to Figure 26.

R Schneider; R. Mesquita; H. Altena; T. Müller; P. Seemann, Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

Evolution on the microstructure and mechanical properties of a new multicomponent near-Alpha Titanium Alloy after rolling and heat treatments

Beijing University of Technology, China, presented the microstructure and mechanical properties of a new type of multi-component near-α titanium alloy sheet after rolling, 700°C aging, and 800°C aging in a new paper.

 The results show that the strength of the alloy after aging at 700°C increases from 1156 MPa to 1304 MPa, respectively, but decreases to 1246 MPa with the aging temperature increasing. The ductility of the alloy aged at 700°C is lower than that of the rolled state, but the ductility increases slightly with the aging temperature increasing. The effect of aging heat treatment on the microstructure and precipitation behavior of alloy plates has been studied and compared with alloys before aging. 

After heat treatment, the content of primary α decreases from 25% to 5%, respectively. Two kinds of silicide precipitate at different positions, with the large-size spherical silicide being (Ti, Zr, Nb)5Si3, and the small-size fusiform silicide being (Ti, Zr, Nb)6Si3, respectively. Ti3Al was precipitated in the primary α phase, during the aging process. The silicides exhibit the strengthening effect on the alloy, but the effect weakens when the silicides grow up. The loss in ductility is mainly attributed to the precipitation of the α2 phase after aging treatment. However, ductility is improved after applying higher aging temperatures as the size of the α2 phase becomes smaller, and the distribution of them tends to become dispersed.

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A ‘green’ Seco/Warwick vacuum furnace for wind power plants

Seco/Warwick, Meadville, Pa., has been chosen by a recognized manufacturer of wind power plants to deliver a vertical vacuum furnace designed to perform low-pressure carburizing for the large structural elements (gearboxes) used in wind power plants. 

The solution on order combines the advantages of two technologies: atmospheric and vacuum processing. The furnace is designed for low-pressure carburizing oversized parts, made possible due to a very large, vertical heating chamber, while the furnace pit structure saves space in the production facility. The Pit-LPC technology is a modern alternative to atmosphere carburizing. Its main advantage is the ability to carry out efficient and effective carburizing in a much shorter time than in atmospheric furnaces. The vacuum processing solution provides more than twice the productivity, and consequently lower process costs and a quick investment return.

The main advantage of this furnace is the ability to open the furnace at process temperature at the end of the cycle. This is the advantage of atmospheric furnace technology implemented within a vacuum furnace. This type of solution combines the advantages of an atmospheric furnace with the advantages of a vacuum furnace, which include: elimination of the oxidation effect at the grain boundary, process purity, and heating uniformity. The product solves the problem of high energy and process gas consumption by the partner’s old furnaces, and shortens the carburizing process, which significantly improves efficiency and production costs.

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One Minute Mentor: Horizontal Retort Furnace

Gas nitriding and nitrocarburizing processes can be processed with fixed gasifying amounts of ammonia, nitrogen, and, for nitrocarburizing, a carburizing and oxidizing agent. However, this does not produce consistent results if different load surfaces are treated with the same fixed gasifying amounts. Furthermore, especially for nitriding processes, the ammonia gasifying has to be reduced or diluted with nitrogen after several hours because the nitrogen uptake of a load decreases. Another quite popular method, usually called the “Floe process,” is a two-step nitriding, where two different nitriding temperatures and different gas flows allow adjustment of the nitriding potential (KN) to the requirements.

Therefore, modern gas nitriding and nitrocarburizing furnaces are equipped with sensor systems and a process control unit that allow the measurement and automatic control of the nitriding potential (KN). The figure shows a schematic of a typical horizontal retort furnace. Similar to the vertical execution, a good circulation of the process gas is needed to get uniform results, which can be reached by the use of a muffle and a high circulation rate. Indirect cooling is performed with an external cooling fan, blowing cold air along the retort. 

For more information, click on the link below (subscription required). Then scroll to Figure 24

R Schneider; R. Mesquita; H. Altena; T. Müller; P. Seemann, Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

Quintus Technologies supplies high pressure Flexform press to airframe manufacturer

Quintus Technologies, Vasteras, Sweden, announced that they will supply a high pressure fluid cell press to France’s LAUAK Group, a Tier 1 supplier to the aerospace industry. The press will be installed at the LAUAK Aerostructures factory in Grandola, Portugal, in September 2023. 

Reaffirming its continued commitment to productivity enhancement, LAUAK selected the Quintus model QFC 0.7×1.8-800 press with high pressure technology to bolster its manufacturing efficiency. “The forming press is undoubtedly at the heart of sheet metal production,” says Mikel Charritton, LAUAK Group Managing Director. “Especially in the context of the current aerospace ramp-up, in particular the A320, A350, and B737 programs, LAUAK’s capital equipment investments are strongly influenced by the imperatives of competitiveness. This press significantly increases and secures our production capacity.” Quintus’s proprietary hydroforming process requires only one rigid tool half, an innovation that not only generates significant tool cost savings but also eliminates several forming operations, intermediate heat treatments, and operator dependencies. 

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One Minute Mentor: Gas nitriding equipment

Gas nitriding and nitrocarburizing can be processed in horizontal or vertical chamber furnaces with refractory insulation. However, to allow a quick change of the atmosphere and to avoid influences resulting from previous processes in the same furnace, retort furnaces are preferred.

To enable an acceptable production capacity, large vertical retort furnaces are used. The figure is a schematic sketch of a vertical retort furnace with a compensator for sealing against the atmosphere. Nowadays large horizontal retort furnaces are also used. Horizontal retort furnaces of different size and execution are preferred for nitrocarburizing processes. Similar to the vertical execution, a good circulation of the process gas is needed to get uniform results, which can be reached by the use of a muffle and a high circulation rate. Indirect cooling is performed with an external cooling fan, blowing cold air along the retort. Other designs allow direct cooling of the process gas with an external heat exchanger.

For more information, click on the link below (subscription required). Then scroll to Figure 23

R Schneider; R. Mesquita; H. Altena; T. Müller; P. Seemann, Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

Lindberg/MPH ships mesh belt conveyor furnace for use with powdered metal

Lindberg/MPH, Mich., has announced the shipment of an electrically heated, full muffle, mesh belt conveyor furnace. This furnace is designed for treating pressed powdered material.

The furnace is designed for applications with a maximum process temperature of 1000° C (1832° F) that utilize a nitrogen or clean dry filtered air process atmosphere. The unit is configured with 9 temperature control zones and includes a water-cooling section. The conveyor system features a 14 inch wide mesh belt with belt stop alarm to provide an audible and visual indication in case of a conveyor stoppage.

There are purge chambers at the entrance and exit of this conveyor furnace. In these chambers purge gas flows from perforated plenum chambers above and below the belt and exhaust stacks with adjustable butterfly valves are located at the inner ends of each chamber. Load and unload tables at the entrance and exit of the conveyor provide ease of product transfer for the operator.

The furnace zone temperatures are controlled by Eurotherm controllers. These controllers have advanced PID control with variable overshoot inhibition. A hi-limit Eurotherm controller guards against over temperature conditions in each zone of temperature control.  A visual and audible alert and removal of power to the heating element occur in the event the monitor temperature exceeds a desired set point. 

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Seco/Warwick to supply a vacuum furnace specifically designed for the MRO industry

Seco/Warwick, Meadville, Pa., will supply a vacuum furnace specifically for the maintenance, repair, and operations (MRO) industry. The solution will be utilized for repair solutions for both complex aircraft engines and gas turbines for the energy industry in Hungary.

The furnace on order is a unique solution due to the effective size of the heating chamber. It has been adapted to the AeroSpace Power requirements and has a working area of 1300 x 1000 x 1500 mm. Thanks to this, the furnace can accommodate large components – mainly aircraft parts, as well as gas turbines for the energy sector.

The featured technology on order, in addition to non-standard dimensions, is designed to process work in the presence of two gases: argon (used for partial pressure) and nitrogen, which is used mainly in the cooling process.

Additionally, the furnace will be equipped with a dew point sensor for each of the gases. It is a system which solves one of heat treatment’s very critical operational requirements, which is to control the quality/purity of gas used during the process. Vector also features a partial pressure control system based on three gases (hydrogen, argon, and nitrogen) to help prevent evaporation and sublimation of alloying elements from the load surface during the vacuum heat treatment or vacuum brazing process.

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Constellium to provide closed-loop recycling for the all-new Megane E-TECH Electric

Constellium, Paris,  announced today its agreement with Renault Group to establish a closed-loop recycling process for the all-new Megane E-TECH Electric. 

Aluminum, lightweight and fully recyclable, is the material of choice for the electrification of the automotive fleet, and Constellium is well-positioned to support this transition with advanced products and solutions.

Renault Group has developed a closed-loop recycling process to bring manufacturing scrap from the stamping process directly back to Constellium, resulting in a reduced CO2 footprint. Based on best practices to avoid mixing 5xxx and 6xxx alloys and to compact scrap for optimal logistics at Renault Group, the closed-loop process will recycle these alloys, so that they can be reused in Renault Group’s production without any loss of properties, and overall with no downcycling.

Constellium, a full-service supplier of rolled and extruded aluminum solutions for the global automotive market, supplies aluminum for 1 in 4 vehicles produced in Europe and the U.S. We help automakers produce lighter, safer and more fuel-efficient vehicles, as well as electric vehicles with greater range. Renault Group is supplied by Constellium’s ASI-certified facility in Neuf Brisach, France.

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One Minute Mentor: Continuous Operating Furnaces for Tool Steel Strips

The continuous heat treatment of tool steel is applied to low- or medium-alloyed carbon steel strips as well as martensitic stainless steels. The described lines produce high-quality strip with respect to uniform structure, flatness, and bright surface finish. Steel grades with 0.4 to 1.2% C, low and high alloyed, can be processed. Strip dimensions range between 10 to 750 mm (0.4 to 29.5 in.) wide and 0.05 to 4 mm (0.002 to 0.16 in.) thick. High quenching rates are necessary, especially for plain carbon steels. Cooling gradients of up to 600 K/s are possible in a molten lead-bismuth quench. Because two-stage quenching technology provides considerable advantages over quenching in oil, this method has been adopted worldwide. It is also possible to achieve isothermal transformation to bainite and pearlite using a molten metal quench, so this type of hardening and tempering line is extremely versatile.

The configuration of a high-performance line involves an entry and exit section of the strip handling equipment (Fig. 10). The hardening section consists of the austenitizing furnace, the molten metal quench or hydrogen quench, and a martensite cooler. Beyond the martensite cooler the strip is martensitic and fully hardened, and then it passes through the tempering section—consisting of a leveling furnace, tempering furnace equipped with an atmosphere recirculation system, and an atmosphere jet cooler—to finally leave the facility, completely flat, with a bright surface finish and tempered to very uniform tensile strength.

For more information, click on the link below (subscription required). Then scroll to Figure 10

R Schneider ; R. Mesquita ; H. Altena ; T. Müller ; P. Seemann,Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958